The present disclosure relates to a RF (Radio Frequency) switch.
In accordance with the development of wireless communications technology, various communications standards have been developed simultaneously. In addition, in accordance with the miniaturization of wireless communications modules and improvements in the performance of portable communications terminals, the need for individual portable communications terminals to conform to a plurality of communications standards has become apparent. Therefore, the amount of frequency bands that an individual portable communications terminal should be operable with has increased.
That is, existing second-generation (2G) and third-generation (3G) communications technologies have been supplemented with new communications technologies, such that portable communications terminals using fourth-generation (4G) communications schemes such as Long Term Evolution (LTE) have been developed. In addition, in the area of Wi-Fi communications, portable communications terminals have been implemented with the ability to operate with the IEEE 802.11ac standard in addition to the existing IEEE 802.11b/g/n to enhance marketability thereof.
In accordance with this trend, there has also been demand for support for various frequency bands within a radio frequency (RF) front end field. For example, support for various frequency bands with respect to a RF switch positioned on a signal path between an antenna and an RF chipset has been demand. Therefore, a Single Pole Double Throw (SPDT) type switch has been used in various applications.
RF switches should be able to significantly decrease insertion loss in order to decrease loss of a signal and have excellent isolation properties, in order to significantly decrease interference between various frequency bands.
In addition, recently, a process technology based on a field effect transistor (FET) such as a complementary metal oxide semiconductor (CMOS) switch, or the like, has been developed. However, in order to maintain high linearity or endure high power, a negative voltage smaller than 0 has been required as a voltage between a source-drain and a gate.
The following Related art Document (Patent Document 1), which relates to a switch circuit and a method of switching a RF signal, discloses that a sine wave is generated using a separate oscillator, or the like, and a negative voltage is generated using a charge pump, or the like. However, in Patent Document 1, the separate oscillator and charge pump are required, and a delay may occur in generating the negative voltage using the oscillator and the charge pump.